THE CANADIAN ENTOMOLOGIST. 293 



First abdominal segment alone much narrowed, not longer than 

 wide, and nearly as wide as the base of second, unarmed 

 beneath ; ventral segments 3-5 usually with a transverse 



grooved line Cerceris, Latreille. 



First and second abdominal segments narrowed, the first longer 

 than wide, the second subpyriform, the two united resembling 

 the head and neck of a bottle, and both armed beneath with a 



tooth or thornlike process Didesmus, Dahlbom. 



Subfamily II. — Philanthidse, 

 This group is distinguished from the preceding by the normally 

 shaped femora, and by the venation of the hind wings, the cubitus being 

 interstitial with the transverse median nervure, or originating a little 

 before it, but never originatiiig very far beyond it. 



The species falling in this subfamily also seem to have quite 

 different habits, for whereas those of the former prey upon beetles, those 

 in this group, so far as have been observed, prey only upon bees. Apis, 

 HalidtiSy Andrejia, etc. 



Nine genera have been recognized, distinguishable by characters 

 made use of in the following table ; 



Table of Genera. 

 Eyes not at all emarginate within ; marginal cell at apex more or less 

 distant from the costal margin, or subtruncate, tvith a slight 



appendage 2. 



Eyes with a more or less distinct emargination within ; marginal cell 



at apex attaining the costal margin, without an appendage 4. 



2. Front wings with the second discoidal cell less than twice as long as 

 wide at apex, the median and submedian cells equal or nearly. ... 3. 

 Front wings with the second discoidal cell fully twice as long as wide 

 at apex, or even longer. 



Third cubital cell, along the cubitus, about twice as long as along 

 the radius ; pygidium in $ quadrangular, concave above, the 

 clypeus margined anteriorly, but not dentate ; $ with the 

 pygidium triangular, the clypeus anteriorly 



^ 3-dentate Clypeodon, Patton. 



Third cubital cell, along the cubitus, usually more than twice as 

 long as along the radius, sometimes thrice as long ; i)ygidium 

 in 9 triangular, not concave above, either flat or subconvex, 

 the clypeus 3 to 5 dentate ; $ with the pygidium most 

 frequently semicircular, or rarely obtusely 

 triangular Aphilanthops, Patton, 



